Any ideas?

My CC light on the dash comes on when I hit the button to activate the system, but when I set the speed I get a surge of throttle then nothing, just coasting. Same when I hit the reset speed option, a surge of throttle and then coasting. Never actually holds the speed anymore. Everytime you hit the set lever it surges for a split second then starts to coast.

 

I have the exact same problem. After I had the IPD intake plenum and 75mm n/a TB installed my cruise control doesn't work. Greg at RSS who sold me the parts said it may have something to do with the wiring setup of the TB being different for a GT2. He said he would look into it and get back to me. Its been like 2 weeks and word from him yet.

Did you do anything different to your car that might have affected the cruise control?